The present invention relates to an improved bearing assembly. Bearings, generally, are simply surfaces or interfaces where moving parts of a device interface with each other in a non-engaged fashion. (I.E. gears or pinions are not bearings for purposes of this context.) Historically, these surfaces have either slid against each other, or been provided with rolling elements which minimize sliding friction and wear. The standard example of the latter is the ballbearing, which incorporates one or more spherical rolling elements (“balls”) which are captive between two rotating members of the device. Rather than have a direct planar or linear interface between the rotating members, the balls bear any mechanical load and allow the rotating members to spin freely against each other.
While ball bearings and similar devices incorporating rolling elements of various shapes (all hereafter balls, even if they are not spherical) are both well known in the art and highly useful, they have several shortcomings. First, such balls are solid and usually made of very hard, dense materials to improve load-bearing strength and durability. This means that they are highly inelastic, so when mechanical shocks are forced onto the system, the balls can gouge into the channels in the device through which they roll, be deformed themselves, or both. Over time this causes vibration and heat to build up due to less symmetrical rolling. Also, they must be made with extreme precision, as they cannot flex. This means that for high-speed, high-precision uses, ball bearings as currently used in the art are extremely difficult to manufacture. Any failure of precision will result in a bearing which wears out very quickly and may damage the larger device. A bearing assembly which did not suffer from these limitations would be a useful invention.
Another major shortcoming of ball bearings as currently practiced is that in high speed axial and radial loaded bearings, to maintain stability in three dimensions two rings of balls are necessary. If only one ring is used in such applications, the bearing will define a single plane, and can skew or cant even if it maintains a consistent planar shape in two dimensions. Thus four separate channels for the balls to roll in (hereafter generally “raceways,” whether the bearing is self-contained or defined by channels in otherwise integral parts of the device) are required and a larger number of balls, any of which can be a point of failure, are required. A bearing assembly which did not suffer from this limitation would be a useful invention.
Finally, as the balls are solid, it is physically impossible for them to intersect each other. This means that only a single ball can ever take the load in any given ball-diameter length of the raceway, and functions as a major limiter on the number of balls which can be used in a bearing of any given size. Both of these limitations mean that a ball failing or departing from required tolerances has an effect which cannot be compensated for directly beyond certain limits. A bearing assembly which did not suffer from this limitation would be a useful invention.
It is common in the art for balls to be held captive in “cages,” which are rigid structures which hold them at a fixed interval in the raceway. This insures proper spacing and prevents the balls from rubbing on each other, but adds a new potential point of failure. Cages are single pieces, of the appropriate diameter to fit within the raceway and hold the balls as specified without interfering with their rolling movement. If a cage breaks, bends, or warps, it can impair the efficiency of the bearing or even cause catastrophic failure. If this happens, the entire cage must usually be replaced, as they are also required to fit within specific precise tolerances. A bearing assembly incorporating a cage which did not suffer from this limitation would be a useful invention.
The present invention addresses these concerns.